Conventional processing systems include system configuration information which is used during actions such as system boot-up. Such system configuration information can be in the form of software or program code which may be stored in non-volatile memory (NVM). As known in the art, NVM can retain stored information even when it is not powered. Therefore, the system configuration information stored in the NVM will not be lost when the system is powered down. Accordingly, the system configuration information may be made readily available, for example, during the boot-up process, before the system is fully powered up and operational. Correct use of the system configuration information may be crucial to proper configuration, resource allocation, and general health of the system. Therefore it is important to protect the system configuration information from damage or corruption. If the configuration information was to get corrupted, or if configuration information is read incorrectly or improperly utilized during the system boot-up, then severe and possibly irreparable damage could occur to the system.
The system may come under attack, wherein proper functioning of the system may be disrupted by forcing the configuration information to be read incorrectly. Such attacks may be deliberate, for example, initiated by malicious agents, or they may be triggered inadvertently due to unwanted changes in operating conditions. In one example, the system may come under attack when power supplied to the NVM is lowered from normal read voltage when a read operation is performed on the NVM. When subjected, for example, to a low read voltage that is lower than a normal or standard read voltage used during normal or healthy operating conditions pertaining to the NVM, the ability for corresponding read circuitry to correctly read the contents of the NVM will be affected, and the configuration bits read out under such conditions may be incorrect or different from the programmed configuration bits which were stored in the NVM. Accordingly, the system can be tricked into incorrectly reading configuration bits by lowering read voltage during a read operation on the NVM, and this form of attacking the system is known as a power attack. Conventional processing systems do not have robust mechanisms in place to protect the systems from such power attacks. Accordingly, there exists a need to detect and protect the system from harm in the event of such power attacks.